Now that you are in college, you may hear different professors discuss assignments asking you to find sources (like books and journal articles) with specific characteristics such as:
Scholarly or academic
Any of these sources may be considered credible sources, but from this point on, it is up to you to evaluate them to determine if their credibility is useful for your particular need. Typically scholarly, and especially peer-reviewed, are considered credible just by the nature of their publication process.
Extremely important disclaimer: NAU instructors don't consistently define source qualities the same way. In fact, many instructors use these words interchangeably:
So, if you are working on an assignment and you need to find sources that have certain qualities, you'll need to make sure you know how your instructor defines those qualities. You may also want to think about how well the material you are reviewing fits in with all the other research you are gathering. Does it all fit together and support your work?